Calibration of adjustable filters

Abstract

A filter controller. In one embodiment, the filter controller includes a first mechanism for providing an input signal to an adjustable filter. A second mechanism measures a response of the adjustable filter to the input signal and provides a second signal in response thereto. A third mechanism sets one or more parameters of the adjustable filter in response to the second signal. In a more specific embodiment, the adjustable filter includes one or more sub-filters, such as a canceller filter, which may be any filter that employs one or more portions or versions of a signal to selectively cancel one or more portions or versions, such as frequency components, of the same signal.

1. A filter controller comprising:
 a reference signal generator that generates a known reference signal based on a control signal and provides the known reference signal to an adjustable filter; 
 a detector that measures a response of the adjustable filter to the known reference signal and provides a detector signal in response thereto; and 
 a control processor that sets one or more parameters of the adjustable filter in response to the detector signal. 
 
     
     
       2. The filter controller of  claim 1 , wherein the control processor provides the control signal and the one or more parameters include values associated with one or more circuit elements. 
     
     
       3. The filter controller of  claim 2 , wherein the one or more circuit elements include one or more variable capacitors and the values associated with the one or more circuit elements comprise capacitance values of the one or more variable capacitors. 
     
     
       4. The filter controller of  claim 1 , wherein the one or more parameters include one or more gain settings for one or more VGAs included in the adjustable filter. 
     
     
       5. The filter controller of  claim 1 , wherein the adjustable filter includes a plurality of sub-filter elements and switches between ones of the plurality of sub-filter elements. 
     
     
       6. The filter controller of  claim 5 , wherein the plurality of sub-filter elements include a canceller filter, a bandpass filter, and a notch filter. 
     
     
       7. The filter controller of  claim 6 , wherein the canceller filter includes a Quality factor Enhancer (QE) resonator or a group delay adjusting device. 
     
     
       8. The filter controller of  claim 7 , wherein the control processor further adjusts one or more values of one or more circuit elements of the QE resonator or the group delay adjusting device. 
     
     
       9. The filter controller of  claim 8 , wherein the control processor further
 sets an input signal to the QE resonator so that an output of the QE resonator exhibits an oscillation frequency, 
 compares the oscillation frequency to a reference frequency, 
 generates a difference signal in response thereto, and 
 adjusts the one or more circuit values of the one or more circuit elements of the QE resonator to reduce or minimize the difference signal. 
 
     
     
       10. The filter controller of  claim 6 , wherein the canceller filter includes a phase shifter. 
     
     
       11. The filter controller of  claim 10 , wherein the control processor further adjusts a notch frequency of a frequency response of the canceller filter by inputting a pilot signal at a first frequency to the phase shifter and adjusts one or more Quality factor Enhancer (QE) resonators or group delay adjusting devices of the canceller filter so that a power level of an output signal of the canceller filter is reduced or minimized at the first frequency. 
     
     
       12. The filter controller of  claim 11 , wherein the first frequency corresponds to a desired notch frequency of the canceller filter. 
     
     
       13. The filter controller of  claim 6 , wherein the canceller filter is characterized by a notched frequency response. 
     
     
       14. The filter controller of  claim 1 , wherein the control processor further determines the one or more parameters of the adjustable filter based on a circuit environment of the controllable filter. 
     
     
       15. The filter controller of  claim 14 , wherein the control processor further establishes one or more values of the one or more parameters based on a temperature measurement of the signal environment. 
     
     
       16. The filter controller of  claim 14 , wherein the control processor further adjusts one or more of the parameters at predetermined time intervals. 
     
     
       17. The filter controller of  claim 14 , wherein the control processor further adjusts one or more of the parameters in response to a channel change detected in a circuit environment in which the adjustable filter is positioned. 
     
     
       18. The filter controller of  claim 14 , wherein the control processor further sets one or more parameters of one or more notch sub-filters of the adjustable filter to suppress output power of the notch sub-filters at one or more desired frequencies. 
     
     
       19. The filter controller of  claim 14 , wherein the control processor further sets one or more parameters of one or more bandpass sub-filters of the adjustable filter to increase or maximize output power of the one or more bandpass sub-filters at one or more desired frequencies. 
     
     
       20. The filter controller of  claim 1 , wherein the control processor further selectively calibrates each bandpass sub-filter of the adjustable filter as a notch filter. 
     
     
       21. The filter controller of  claim 1 , wherein the control processor further selectively calibrates each notch filter of the adjustable filter as a bandpass filter. 
     
     
       22. A method for implementing dynamic filter calibration, the method comprising:
 providing, by a reference signal generator, a known reference signal to an adjustable filter based on a control signal; 
 sensing, by a detector, at least one condition of the adjustable filter and providing a first signal in response thereto; 
 determining, by a control processor, one or more values for one or more circuit parameters of the adjustable filter in response to the detector signal; and 
 setting, by the control processor, the one or more circuit parameters of the adjustable filter based on the one or more values to thereby selectively adjust a frequency response of the adjustable filter. 
 
     
     
       23. The method of  claim 22 , wherein sensing includes measuring, by the detector, a temperature of an environment in which the adjustable filter is positioned and providing, as the first signal, a temperature signal in response thereto. 
     
     
       24. The method of  claim 23 , wherein determining further includes referencing, by the control processor, a look-up table using the temperature signal to facilitate determining the one or more values. 
     
     
       25. The method of  claim 22 , wherein sensing includes determining, by the sensor, a channel setting of a system that is in proximity to the adjustable filter. 
     
     
       26. The method of  claim 22 , wherein setting includes applying, by the control processor, control signals to one or more VGAs included in the adjustable filter to shift a frequency response of the adjustable filter. 
     
     
       27. The method of  claim 26 , wherein setting further includes adjusting, by the control processor, a frequency response of a notch sub-filter included in the adjustable filter. 
     
     
       28. The method of  claim 22 , wherein setting includes applying, by the control processor, one or more control signals to one or more controllable capacitors included in the adjustable filter. 
     
     
       29. The method of  claim 28 , wherein setting further includes adjusting, by the control processor, a resonating frequency of a Quality factor Enhancer (QE) resonator of the adjustable filter. 
     
     
       30. The method of  claim 22 , further comprising
 storing, by the control processor, the one or more values for one or more circuit parameters in a look-up table. 
 
     
     
       31. The method of  claim 30 , further comprising selecting, by the control processor, the one or more values for the one or more circuit parameters among values stored in the look-up table for the one or more circuit parameters. 
     
     
       32. A method for calibrating a circuit module, the method comprising:
 providing a known reference signal to the circuit module so that the circuit module resonates, yielding an oscillating output signal in response thereto; 
 comparing a resonating frequency characterizing the output signal to a reference signal characterizing the known reference signal; and 
 adjusting one or more parameters of the circuit module in response to the comparing. 
 
     
     
       33. A method for calibrating a circuit module, the method comprising:
 providing a known reference pilot signal to the circuit module, the known reference pilot signal being characterized by a frequency corresponding to a desired notch frequency of a frequency response of the circuit module; and 
 adjusting one or more characteristics of one or more circuit components of the circuit module until an output power of the circuit module exhibits a desired characteristic. 
 
     
     
       34. The method of  claim 33 , wherein the desired characteristic includes the output power of the circuit module reaching an approximate minimum. 
     
     
       35. The method of  claim 33 , wherein the desired characteristic includes the output power of the circuit module reaching an approximate maximum.